Coffee machine



FIG. 1 is a perspective view of a coffee machine showing my new design;

FIG. 2 is a front view of my new design;

FIG. 3 is a back view of my new design;

FIG. 4 is a right side view of my new design;

FIG. 5 is a left side view of my new design;

FIG. 6 is a top view of my new design; and,

FIG. 7 is a bottom view of my new design. 

The ornamental design for a coffee machine, as shown and described. 